. >>> sinkholes opening up in san francisco forced officials to red tag three homes. this is following a water main break. the 61-year-old water pipe gave way thursday morning and the cause is unclear. two other homes in the neighborhood have been watched in case soil conditions change. >>> toxic vapors in their homes, endangering their lives. that is what an angry crowd talked about today. kpix reporter is in mountain view where the problem goes back decades, don? >> reporter: it is unnerving for many that live here who thought the toxic chemical has been under control for years can. now moving about in their homes and showing up in concentrations. >> reporter: vapors tce that pollutes the ground water of this part of silicone valley. >> what are the concerns that bring you here? what are you thinking about? >> health. number one, health, secondly, property values. >> reporter: the history goes back to the '60s, '70s, '80s when they dumped it and it ended up in the ground water t. seemed controlled for years new concerns emerged last year from vapors seeped into area